spring
Spring
IOC
控制反转(Inversion ofControl):将一些对象的创建权交给Spring
需要的jar包
//日志接口 com.springsource.org.apache.commons.logging-1.1.1.jar //日志实现 com.springsource.org.apache.log4j-1.2.15.jar spring-beans-4.2.4.RELEASE.jar spring-context-4.2.4.RELEASE.jar spring-core-4.2.4.RELEASE.jar spring-expression-4.2.4.RELEASE.jar
接口和类
public interface UserDao {
public void save();
}
public class UserDaoImpl implements UserDao {
@Override
public void save() {
System.out.println("UserDaoImpl...save...");
}
}
传统方式调用
UserDao userDao = new UserDaoImpl(); userDao.save();
如果底层实现切换,需要修改源码,Spring IOC就是用来在不修改源码的情况下对程序进行扩展.
IOC实现
配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="userDao" class="com.swifter.demo1.UserDaoImpl"></bean>
</beans>
调用
ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
UserDao userDao = (UserDao) classPathXmlApplicationContext.getBean("userDao");
userDao.save();
只需要业务代码,配置文件,反射和工厂不需要实现.
IOC和DI
- IOC: 控制反转
- ID: 依赖注入,前提是必须有IOC环境,Spring管理这个类的时候将类的依赖属性设置进来
Spring工厂类
- BeanFactory
- ApplicationContext 实现类 FileSystemXmlApplicationContext, ClassPathXmlApplicationContext
Bean相关配置
- id 使用了约束中的唯一约束,不能包含特殊字符
- name 可以包含特殊字符
Bean声明周期
<bean id="customerDao" class="com.swifter.demo2.CustomerDaoImpl" init-method="init" destroy-method="destroy">
</bean>
public class CustomerDaoImpl implements CustomerDao {
public void init() {
System.out.println("CustomerDaoImpl...init...");
}
public void destroy() {
System.out.println("CustomerDaoImpl...destroy...");
}
@Override
public void save() {
System.out.println("CustomerDaoImpl...save...");
}
}
调用
ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
CustomerDao customerDao = (CustomerDao) classPathXmlApplicationContext.getBean("customerDao");
customerDao.save();
classPathXmlApplicationContext.close();
作用范围
//scope是singleton会调用destroy方法,但是prototype不会调用, 默认是singleton
属性注入方式
- 构造方法
- set方法
构造方法
<bean id="car" class="com.swifter.demo4.Car">
<constructor-arg name="name" value="QQ"/>
<constructor-arg name="money" value="20000"/>
</bean>
public class Car {
private String name;
private Double money;
public Car() {
}
public Car(String name, Double money) {
this.name = name;
this.money = money;
}
@Override
public String toString() {
return "Car{" +
"name='" + name + '/'' +
", money=" + money +
'}';
}
}
set方法
<bean id="car2" class="com.swifter.demo4.Car">
<property name="name" value="奔腾"/>
<property name="money" value="2000"/>
</bean>
public class Car {
private String name;
private Double money;
public void setName(String name) {
this.name = name;
}
public void setMoney(Double money) {
this.money = money;
}
public Car() {
}
public Car(String name, Double money) {
this.name = name;
this.money = money;
}
@Override
public String toString() {
return "Car{" +
"name='" + name + '/'' +
", money=" + money +
'}';
}
}
设置对象类型属性
<bean id="employee" class="com.swifter.demo4.Employee">
<property name="name" value="王五"/>
<!--value设置普通类型, ref设置对象类型-->
<property name="car" ref="car"/>
</bean>
public class Employee {
private String name;
private Car car;
public void setName(String name) {
this.name = name;
}
public void setCar(Car car) {
this.car = car;
}
@Override
public String toString() {
return "Employee{" +
"name='" + name + '/'' +
", car=" + car +
'}';
}
}
p名称空间
- 普通属性: p:属性名="值"
- 对象属性: p:属性名-ref="值"
xmlns:p="http://www.springframework.org/schema/p" 要加上 <!--p名称空间方式--> <bean id="car3" class="com.swifter.demo4.Car" p:name="qq" p:money="200" />
--EOF--
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